The present invention relates to a light positioning device, and in particular to a light positioning device capable of reducing errors in assembly of a light guide plate, a light source assembly and a frame thereof.
LCD devices are generally multiple-layer structures comprising a light guide plate, a light source assembly, an LCD panel, a reflective plate, a diffusing plate and a frame. Conventionally, the light source assembly is first fixed on the frame and the light guide plate is then fitted into the frame.
Referring to FIG. 1, one side 11 of a conventional frame 1 is formed with a plurality of protrusions 12 and a plurality of recesses 13. The protrusions 12 and recesses 13 are alternately formed on the side 11.
Referring to FIG. 2, a conventional light source assembly 2 comprises a flexible circuit board 21 and a plurality of light source modules 22. Each light source module 22 comprises at least one light-emitting diode (LED).
Referring to FIG. 3A, the light source assembly 2 is first disposed on the side 11 of the frame 1. At this point, the light source modules 22 of the light source assembly 2 are respectively received in the recesses 13 of the side 11. A light guide plate 3 is then fitted into the frame 1 and abuts the light source assembly 2 to form a light positioning device 10.
Specifically, a tolerance or error may occur during manufacture of the frame 1. Further, assembly errors may occur between the light guide plate 3 and the frame 1 and between the light source assembly 2 and the frame 1. The cross section of the assembled light positioning device 10 is shown in FIG. 3B. Accordingly, a gap A exists between a light-input surface 31 of the light guide plate 3 and a light-output surface 23 of the light source modules and a displacement B exists between the central line of a LED 24 (or the light source module 22) of the light source assembly 2 and the central line of the light guide plate 3. The gap A and displacement B are often large, such that light from the LED 24 (or the light source module 22) cannot be effectively utilized by the light guide plate 3. Thus, the performance of the light positioning device 10 is adversely affected.
Additionally, assembly of the light positioning device 10 is complicated, resulting in increased manufacturing time, manpower and cost.